共查询到20条相似文献，搜索用时 125 毫秒
1.
Laura A. Hogarth William A. Roberts Shelley Roberts Benjamin Abroms 《Learning & behavior》2000,28(1):43-58
We performed six experiments in order to examine the ability of rats to use moving beacons and landmarks as cues to the location of reward on an eight-arm radial maze. In Experiments 1–4, the cues and goals were moved before each trial, and groups in which a single beacon was placed on the rewarded arm, a single landmark indicated that reward was on the arm immediately to the left of a landmark, or two landmarks were placed on each side of the reward arm were compared. The rats rapidly learned to track the reward in the beacon condition, failed to find the reward sooner than chance expectation with a single landmark, and did only slightly better than chance with two landmarks. In Experiments 5 and 6, the rats were trained in five trials per day, with the landmark and goal locations constant over daily rewarded trials, and in two extinction trials that were inserted among the rewarded trials. The rats found the goal arm at substantially better than chance expectancy with both one and two landmarks. Our results, in agreement with data from recent swimming pool experiments (A. D. L. Roberts & Pearce, 1998), show that rats will use the relationship between moving landmarks and a goal in order to find reward. 相似文献
2.
In a series of four experiments with free-flying honeybees, individual foragers were trained with targets of two different colors that contained 5 or 20 μl of 50% sucrose solution. The two targets were singly presented in quasi-random sequences on each visit, with the amount of reward to be found on each target perfectly predictable from its color. The number of training visits (4–32) was varied both within and between experiments, and so also was the relative frequency of trials with the 5- and 20-μl targets (1:1, 2:1, 3:1, and 9:1). At the conclusion of training under each condition, unrewarded responses to the targets were measured in a 10-min extinction test, with the targets presented either separately to two different groups of animals (Experiment 1) or as a pair (Experiments 2–4). When the number of training trials with each target was the same (Experiments 1 and 2), the animals responded more in extinction to the 20-μl target than to the 5-μl target, although there was a decline in the overall level of responding to both targets (an overlearning-extinction effect) as the number of training trials increased. After nine times as many, or only three times as many, training trials with the5- μl target as with the 20-μl target, the animals responded more in extinction to the 5-μl target (Experiment 3); after twice as many training trials with the 5-μl target as with the 20-μl target, there was equal responding to both (Experiment 4). The preferences shown in the choice tests of Experiments 2–4 could be simulated rather accurately on the assumptions of a model previously developed to deal with the discrete-trials choice behavior of honeybees and the further assumption that associative strength grows at a rate increasing with amount of reward to an asymptote independent of amount of reward. 相似文献
3.
In Experiments 1 and 2, honeybee foragers visiting the laboratory were fed on targets of two different colors, one containing 5 μl and the other containing 20 μl of 50% sucrose solution. The targets were presented singly in quasi-random sequences on the training visits, after which preference was measured in an unrewarded choice test. In Experiment 1, 16 differentially rewarded training trials with each color were followed by the same number of trials with the color-amount relation reversed; no preference for either color was found in the subsequent choice test. In Experiment 2, 20 differentially rewarded training trials with each color—enough to produce a clear preference for the 20-μl color when given directly after pretraining—were given after 10 feedings to repletion on each color that were calculated to generate near-asymptotic associative strength; no preference for either color was found in the subsequent choice test. In Experiment 3, there were 12 feedings to repletion on one color and, on the other, 12 feedings to repletion followed by 15 trials with a small (5 μl) reward; no preference was found in a subsequent choice test. The results of all three experiments support a nonrepresentational interpretation of the role of amount of reward in the learning of honeybees. 相似文献
4.
Foraging honeybees were trained individually in two-choice spatial problems. Differentially rewarded for spatial alternation in Experiment 1 (“win-shift” training), they showed instead a clear tendency to perseverate—that is, to prefer on each trial the location of reward on the immediately preceding trial. On the basis of the results of Experiments 2 and 3, in which one location was rewarded over shorter or longer series of consecutive trials, an associative interpretation of the perseveration found in the first experiment was rejected in favor of an interpretation in terms of short-term spatial memory. Experiment 4, in which the animals were rewarded on each trial for choosing either location, also showed perseveration. Honeybees, like rats, seem to remember a rewarded location recently visited, but tend to return to it rather than, like rats, to avoid it. 相似文献
5.
Learning in honeybees as a function of amount of reward: Rejection of the equal-asymptote assumption
Foraging honeybees were trained individually with successively presented targets differing in odor, one containing 5 µl and the other 20 µl of a 50% sucrose solution, after which preferences were measured in choice tests. In Experiment 1, there were either 8 training trials with each target, 16 trials with each, or 8 trials with the 20-µ1 target and 16 trials with the 5-µl target. In Experiments 2 and 3, the odor-amount relation was reversed after either 24 or 16 trials with each target. In Experiment 4, differential reward was introduced only after two, four, or six feedings-to-repletion on each target. All of the results could be simulated quantitatively and with considerable accuracy on the assumption that the attractiveness of an odor is given by the strength of its association with sucrose; that asymptotic associative strength is an increasing function of amount of reward; and that choice between two odors is determined by their relative associative strength. 相似文献
6.
In Experiment 1, rats received single-alternation training with 32% or 4% sucrose reward (Phase 1) followed by a shift in reward from 32% to 4%, and vice versa (Phase 2). In Phase 1, high reward facilitated alternation performance over low reward. In Phase 2, performance on rewarded trials increased as reward increased but was unchanged as reward decreased. Performance on nonrewarded trials showed negligible effects of shifts in reward. In Experiment 2, rats received goalbox placements with 32% or 4% sucrose alternated with nonreward in Phase 1; and in Phase 2, they received alternation runway training with the same or the opposite reward from that of placements. Performance on rewarded trials was faster, the higher the reward in runway training; performance on nonrewarded trials was slower, the higher the reward in placements. In Experiment 3, Phase 1 provided placements with 64%, 32%, 16%, or 4% sucrose or dry mash alternated with nonreward; Phase 2 provided alternation runway training with dry mash reward. Alternation prerformance developed more rapidly, the higher the sucrose concentration in placements. Only 64% sucrose produced performance superior to that for dry-mash placements. 相似文献
7.
Rats were exposed to three-trial series consisting of reinforced (R) trials and one nonreinforced (N) trial in a fixed order,
RRN and RNR (Experiments 1 and 2) or NRR and RRN (Experiment 3), on extended visually distinct runways in a T-maze. When initially
presented with the same sequence on each series in a session (separate presentations) with the same runway on all trials within
a series (Experiments 1 and 3), all the rats developed slower running speeds on N than on R trials. When a runway was sometimes
changed between the first and next two trials during separate presentations training (Experiment 2) or both sequences were
later intermixed within each session in each experiment, only rats exposed to each sequence on a specific runway maintained
these serial running patterns. Rats displayed serial running patterns on a test RNN sequence similar to that on the RNR sequence
(Experiment 2), as would be predicted by an intertrial association model of serial pattern learning (Capaldi & Molina, 1979),
but responded on test RRR and NRN sequences (Experiment 3) as would be predicted by an ordinal-trialtag/intratrial association
model (Burns, Wiley, & Payne, 1986). Results from test series of free-choice trials in Experiments 1 and 2 failed to support
a prediction of the intratrial association model that these rats would integrate RRN and RNR sequences. Rather than always
selecting a baited runway on both the second and the third free-choice trials, the rats only selected a baited runway on the
third trial on the basis of their choice on the second trial, as would be predicted by the intertrial association model. Only
after experiencing all possible outcome sequences during forced-choice training in Experiment 3 did these rats predominantly
select a baited runway on every free-choice trial. 相似文献
8.
In Experiment 1, hungry rats received 30 rewarded runway trials and then either extinction trials followed by retention tests or just retention tests. Different groups were tested after retention intervals of 1 min, 1, 3, or 24 h, or 30 days. Retention of extinction training was a nonmonotonic, cubic function of time for the early portion of the response chain, with good retention at 1 min and 3 h and little retention at 1 h, 24 h, or 30 days. In the latter portions of the response chain, retention of extinction decreased monotonically with time. Retention following reward-only training varied little in time, though slight losses occurred after 30 days. Experiments 2–3 differed from Experiment 1 in imposing nonchoice discrimination training (reward vs. nonreward) instead of extinction following 30 rewarded trials. After different time intervals (.017, .75, 1.25, 3, and 24 h in Experiment 1; and .017, 1, and 3 h in Experiment 2), retention tests revealed poorest discrimination at intermediate intervals in the initial portion of the response chain, i.e., a Kamin effect appeared. The deficit seemed the result of a loss of response suppression to the cue that signaled nonreward. In latter segments of the response chain, a Kamin effect tended not to appear. Implications for a number of observations and theoretical views are noted. 相似文献
9.
The relative preferences of four rhesus monkeys for reward probability versus reward amount when they were maintained on a low-protein (3.35%) diet were compared with those demonstrated when they were fed an adequate (13.4%) protein diet. Four stimulus objects, each signifying a different combination of reward frequency and amount (100%-one piece, 50%-2 pieces, 33%-three pieces, or 25%-four pieces), were presented in pairs, one pair per daily session, with trial schedules providing the same amount of reward within each set of 12 trials. Selections of the more frequently rewarded objects, but with lesser amounts per trial, were significantly higher during the low-protein phase than during either the preceding or the following normal-diet phases. Protein deprivation produces a changed motivational state making these animals less tolerant of infrequent or postponed reinforcement. 相似文献
10.
In three experiments, we studied the consequences of ejaculation upon the frustrative or contrast response of male rats exposed
to reward downshift situations (i.e., surprising changes from 32% to 4% sucrose solutions). Similar to what has been found
after treatment with anxiolytic agents, consummatory suppression was partially reversed by previous ejaculations in a second
postshift trial (Experiments 2 and 3), such a result not having been obtained in a first postshift trial (Experiment 1). Moreover,
the effect of ejaculations upon males' behavior during a second postshift trial was transitory, disappearing when assessed
during the third and fourth postshift trials (Experiment 3). These results are in accordance with both Amsel's (1958, 1992)
frustration theory and Flaherty's (1996) multistage hypothesis of successive negative contrast; the diverse factors that are
known to modulate contrast effects are considered, including an interpretation of the present data in terms of the anxiolytic-like
effect of the ejaculation. 相似文献
11.
Paul T. P. Wong 《Learning & behavior》1978,6(1):82-93
Three runway experiments tested a stage model of extinction which postulated an orderly succession of three qualitatively different stages: habit, trial and error, and resolution. The model predicted that Stage 1 should be characterized by perseveration of habitual routes (i.e., response persistence) and the absence of competing responses; Stage 2, by an increase in investigatory behavior (response variation and hole exploration) and biting behavior; Stage 3, by a decrease in the competing responses of Stage 2 and continued increase in goal avoidance and substitution behavior (e.g., sand-digging). These predictions were largely confirmed. Further, Experiments 1 and 2 showed that, as expected by the model, continuous reinforcement (CRF) resulted in more practice of habitual routes in acquisition and greater response persistence, while partial reinforcement (PRF) resulted in more route variation and hole exploration in acquisition and greater goal persistence which was attributable to prior reinforcement of a trial-and-error coping strategy. Results of Experiment 3, which combined training trials and reward magnitudes orthogonally, supported the prediction that response persistence was positively related to training trials, and goal persistence negatively related to reward magnitudes. All three experiments demonstrated an inverted-U function in investigatory and biting behavior, as predicted by the stage model. 相似文献
12.
Rats were trained to find the hidden platform in a Morris pool, whose location was defined by reference to a small number
of landmarks around the circumference of the pool. In each of three experiments, an experimental group was trained on alternate
trials with two different subsets of three of the available landmarks, with the two subsets sharing one landmark in common.
When tested with landmarks drawn from both of their training configurations, but without the landmark common to the two sets,
they had no difficulty in locating the platform. In Experiment 1, they performed at least as well as a group trained with
all the available landmarks present on every trial. In Experiment 2, they performed significantly better than a group trained
with two different subsets of landmarks that shared no one landmark in common. 相似文献
13.
In the blocking phase of three experiments, rats had to find a submerged platform beneath a spherical landmark in one corner
of a triangular pool. Prior to this treatment, they were required to find the platform relative to either a sphere above it
(blocking groups) or a rod attached to it (control groups). The position of the platform changed from trial to trial for the
initial training. The sphere did not restrict learning about the geometric cues provided by the triangular arena in the blocking
phase when 12 sessions of initial training took place in either the triangular (Experiment 1) or a circular (Experiment 3)
pool. Blocking was observed, however, after 24 sessions of initial training in either the triangular (Experiment 2) or the
circular (Experiment 3) pool. Thus, blocking of geometric cues by a landmark is possible after extended initial training with
the blocking cue. 相似文献
14.
Steven J. Haggbloom 《Learning & behavior》1980,8(3):424-428
In two differential conditioning experiments, groups of 10 rats each differed with respect to average reward and schedule of reward received in S+. Nonreward (N) occurred on all S? trials. In both experiments, extinction of responding to S? (resistance to discrimination) was extensively regulated by reward sequence and was largely independent of average reward. In Experiment 1, resistance to discrimination was a function of transitions from N to rewarded (R) trials (N-R transitions). In Experiment 2, resistance to discrimination was increased by large reward on the R trial of N-R transitions and decreased by large reward on the R trial of R-N transitions. These schedule effects on resistance to discrimination parallel the effects of comparable schedules on resistance to extinction following partial reinforcement. The results are discussed in terms of sequential theory, reinforcement level theory, and their implications for various schedule manipulations that have previously shown S? behavior to be inversely related to average reward in S+. 相似文献
15.
Wallace R. McAllister Dorothy E. McAllister Stephen E. Dieter James H. James 《Learning & behavior》1979,7(2):165-173
In Experiment 1, four groups of subjects (n = 16 each) were exposed to the situational stimuli of a shuttlebox apparatus for 4 h. Subsequently, 200 two-way avoidance trials were administered (100/day) with either .3- or 1.6-mA shock and with either small or large reward (presence or absence of visual stimuli following the response). Avoidance performance was directly related to shock intensity on both days and to magnitude of reward on the 2nd day. In Experiment 2, four groups of subjects (n = 24 each) were given 4 h of exposure either to the situational stimuli of the shuttlebox or to a neutral box. Then, 10 two-way avoidance trials were given with 1.6-mA shock. Subsequently, subjects were allowed to escape from one of the shuttlebox compartments to an adjacent safe box. Following preexposure to situational stimuli, avoidance performance was superior whereas escape-from-fear performance was inferior. This latter finding demonstrated that less fear of situational cues was present during avoidance training in the preexposed condition. All of these results support the effective reinforcement theory, an extension of two-factor theory, which emphasizes the importance for avoidance learning of the amount of fear of situational cues present following a response. 相似文献
16.
Mongolian gerbils were trained to jump across gaps of randomly varying width in order to obtain a food reward. During training, gerbils learned to jump to each of two landing platforms differing in width. These landing platforms were associated with unique spatial contexts (Experiment 1), local features (Experiment 2), or both (Experiment 3). In test sessions, a landing platform was substituted that was intermediate in width between the two training platforms of novel width, in order to determine whether gerbils could use retinal image size to calibrate distance. Experiments 1 and 2 suggested that gerbils used spatial context but not local feature information to identify the target platforms. In Experiment 3, when the probe platform was presented with the same local feature information and in the same context as seen in training sessions, gerbils over- or underjumped in a manner predicted if they were using the retinal image size of the target to calibrate the distance across the gap. When the probe trials contained a mismatch between context and local feature information, no systematic over- or under-jumps were seen, and jumping accuracy was decreased. Taken together, these results suggest that, in this task, objects are identified primarily on the basis of the spatial context in which they are seen and not on the basis of their local features. 相似文献
17.
In Experiments 1 and 2, rats were trained in a Morris water maze to locate a hidden platform, the location of which in the circular pool was defined by four visual landmarks (A, B, C, and D), spaced at equal intervals around the edge of the pool. Control animals were trained with these four visual landmarks only. But for animals in the overshadowing groups, an auditory component, X, was added to Landmark D. Test trials, given at the end of training, consisted of placing the rat in the pool with no platform present and recording the time rats spent in the platform quadrant. In Experiment 1, the overshadowing group spent less time in the platform quadrant than controls when tested with D, but the two groups performed equally well on test trials that did not use D. We conclude that the auditory Component X overshadowed the visual Landmark D. In Experiment 2, we obtained evidence of reciprocal overshadowing, of D by X and of X by D. The results of Experiment 3 suggested that an appeal to generalization decrement might not be sufficient to explain these overshadowing effects. 相似文献
18.
Rats are typically less accurate in their arm selections in the radial maze over successive trials in a session (Roberts & Dale, 1981). In the present study, rats’ choice accuracy declined when such trials were separated by 2-min (massed) but not by 2-h (spaced) intertriai intervals. Changing intramaze visual/tactile arm stimuli (Experiments 1 and 3) or extramaze landmark stimuli (Experiment 4) between trials weakened the massed-trials effect, but changing the number of food pellets per arm, either alone or in conjunction with changes in intramaze cues (Experiments 2 and 3), did not. The rats also tended to avoid the spatial locations of their last four choices on a previous trial during their first four choices on a current trial, and more so with massed than with spaced trials. These findings indicate that intertriai proactive interference (PI) occurred only with massed trials and was weakened by changing intra- and extramaze cues between such trials. 相似文献
19.
The effect of inhibiting the orienting response on information processing was examined in four experiments. A nonsignal auditory stimulus was presented four times to preweanhng rats either 30 sec or 15 min after they had been placed in an unfamiliar environment (Experiments 1A and 2), shocked (Experiment 1B)5 or experienced a shift in environmental context (Experiment 1C). Both an autonomic (heart rate) and a behavioral componentx of the orienting response to the novel stimulus were recorded. In the 15-min condition, the auditory stimulus elicited a consistent orienting response on the first trial that habituated rapidly with successive trials. In contrast, the auditory stimulus did not elicit a detectable orienting response in the 30-sec condition on any of the four trials. However, when the auditory stimulus was re-presented after a brief retention interval, a comparable level of habituation was seen in both groups. These results demonstrate that animals in the 30-sec condition detected, attended to, and encoded the auditory stimulus even though they did not orient, either autonomically or behaviorally, to that stimulus when it was first presented. This process of response-independent habituation is best described as latent habituation. Like latent learning, latent habituation took place in the absence of any observable change in behavior. The implications of this effect for current theories of habituation and of the orienting response are discussed. 相似文献
20.
Based on several recent demonstrations of a directed forgetting effect in pigeons, three experiments were carried out in an attempt to demonstrate directed forgetting in three squirrel monkeys. During initial training with a delayed matching-to-sample procedure, retention tests were always given for sample stimuli followed by remember cues (R-cues) and were always omitted for sample stimuli followed by forget cues (F-cues). Retention of F-cued items was tested on probe trials after initial training. The first two experiments examined the effects of R- and F-cues on memory for slide-projected pictures, with different pictures used on each trial of a session. In Experiment 1, a complex design was used in which one or two sample pictures were presented on each trial; when two pictures were presented, both could be R-cued or F-cued, or one could be R-cued and the other F-cued. A simpler design was used in Experiment 2, with only single pictures presented as sample stimuli and half the trials within a session R-cued and the other half F-cued. In both of these experiments, no differential retention of R- and F-cued stimuli was found, even at a retention interval as long as 16 sec. In Experiment 3, a series of studies was performed to test for directed forgetting when only two sample stimuli were used repeatedly throughout training and testing. With two pictures as sample stimuli, clear evidence of directed forgetting was found in Experiment 3b. It is suggested that the directed forgetting effect may arise only when a small set of sample stimuli is used. 相似文献